With the development of LED display technology, outdoor applications of LED displays are becoming more and more widespread, and the emergence of small-pitch LED displays has gradually highlighted its advantages as indoor display equipment. It is understood that it has a large number of indoor application cases such as conference centers and security monitoring in the military, transportation, energy and other industries. However, it has not yet been put into operation as a large screen for monitoring in the centralized control room of a power plant. This article will initially explore whether the small-pitch LED display can meet the application needs of this environment.
1 Advantages of large screens in centralized control rooms
1.1 Picture integrity
The picture integrity of the small-pitch LED display is undoubtedly one of its biggest advantages. As a power plant, the main function of the large screen in the centralized control room is to display process images of each system of the power plant, industrial televisions on steam drum water levels, and industrial video images of important equipment and channels in the production area. It not only facilitates the supervision of important data and important processes by operators, but also plays a great assistive role for leaders at all levels to grasp the operating status of the units and direct emergency work on site. The small-pitch LED display has no patchwork effect, perfectly restores the picture, and avoids problems such as the covering and truncation of lines and data in the unit process screen by the patchwork, thereby also avoiding more serious problems such as misjudgment and command.
1.2 Small installation space
The thickness of small-pitch LED display units generally does not exceed 100 mm, and the installation space requirements are relatively low. Only 800 mm of installation and maintenance space is required, which effectively saves floor space and improves the utilization of the centralized control room area. The load of about 90 kg/m2 has little effect on the load of building floors and holes. It is especially suitable for the renovation project of the original centralized control room. It generally will not exceed the design load of the original floor slab and foundation, thus simplifying the implementation process of the renovation project.
1.3 Low maintenance costs
First, due to the small area of the smallest display unit to be replaced in a small-pitch LED display, the LED lights can even be replaced one by one, minimizing the area where maintenance work occurs. Therefore, the cost of spare parts invested in a maintenance work is correspondingly reduced.
Secondly, because the display unit of the small-pitch LED display is small in area, light in weight, and relatively simple to operate, the number of personnel required for maintenance work is not very large, and larger mechanical assistance is generally not required. Therefore, the labor and equipment costs invested in one
maintenance work are effectively reduced.
1.4 Improve the quality of the working environment
The outstanding picture display effect will undoubtedly greatly improve the viewer's comfort under the premise of appropriate viewing distance and appropriate screen brightness. The low power consumption, low heat dissipation and fanless design of the LED lamp itself reduce the impact on the ambient temperature, reduce the generation of noise, and provide a better working environment for operators.
2 Concerns about using large screens in centralized control rooms
Based on the high-brightness characteristics of LED lights and the understanding that its products with a pitch of 3 or more are used in outdoor billboards and indoor welcome screens, it is inevitable to have doubts about whether it is suitable for large screens in power plant centralized control rooms with a 24-hour working system.
2.1 Is it suitable for indoor close viewing?
The high brightness characteristics and excellent protective capabilities of LED lights make them occupy an irreplaceable dominant position in outdoor billboards, especially when they achieve a clear effect that cannot be achieved by other types of screens in outdoor strong light environments and long-distance viewing. However, once used in indoor environments, these two advantages completely turn into disadvantages. The resolution of LED display products with a pitch of 3 or more is very low when viewed at close range, and it is almost impossible to distinguish the displayed content. Moreover, the high brightness will make it very dazzling when viewed at close range. So, can small-pitch LED displays be suitable for indoor viewing? Through the physical viewing experience of LED screens with a pitch of less than or equal to 2.5 mm, it is confirmed that small-pitch LED displays are suitable for indoor close viewing. So, how does it solve the problems of high brightness and poor resolution? First of all, since the indoor application of LED screens has been taken as a research direction, as the process technology of the LED lamp itself has improved, the light-emitting area has become smaller and smaller. With the refinement of the processing technology, the distance between the lamps has gradually shrunk from 2.5 mm to 0.7 mm. Therefore, the resolution problem has been solved in a breakthrough.
Although it cannot compare with the exquisiteness of LCD displays, when the viewing distance is 3m, the overall performance of small-pitch LED displays can already meet the sensory needs. At a viewing distance of 5 m, the clarity of LED displays with spacing of 1.6 mm and 1.9 mm when playing 4K video sources can fully achieve 4K high-definition effects. Secondly, when the brightness of the LED display screen used for indoor viewing is adjusted to 15% to 25% of the standard brightness, the viewing comfort of the human eye will be greatly improved under general indoor lighting conditions. Especially when a pure ink-colored screen plays a black background film source and the viewing distance is 25 cm, the human eye will not feel any discomfort. Although small-pitch LED displays have performed very well indoors, the weaknesses of LED lights are still prominent when they display white. Since the LED display screen has a high contrast ratio, when the same pure ink screen displays a black and white contrast picture, it is obvious that the resolution of the white part is reduced and it feels dazzling. In this case, the viewing comfort can only be enhanced by further reducing the brightness.
2.2 Whether there is permanent damage to human eyes
High-resolution and large-size LED dot matrix color display screens are favored by people on many occasions because of their unique advantages such as high brightness, wide color gamut, and high contrast. At the same time, the photobiological safety of this type of display to the human eye has also attracted people's attention.
According to current international standards, the photobiological safety of LED displays was measured from two aspects: retinal blue light hazard and thermal hazard, and plasma TV and LCD TV prototypes were selected for comparison. The test conclusion shows that under the same brightness and white field conditions, in the blue light band, although the peak brightness of the LED display is higher than that of the other two samples, its narrow band characteristics make the retinal hazard index obtained after weighted integration not higher than that of plasma TVs and LCD TVs. There is no significant difference in the retinal photobiological safety measurement data of the three different displays. Among the three samples, the measurement results of the LED display are even better than the other two displays.
2.3 Is the investment cost too high?
Under the premise of the same display area, 1.6 The cost of a mm-pitch LED screen is about 1.3 times that of a 55-inch DID LCD splicing screen, which is equivalent to the cost of LED backlight DLP. However, due to the outstanding performance of LED displays in long life, the lifespan of small-pitch LED displays is generally 1.8 to 2 times that of DID LCD splicing screens and DLP splicing screens. Based on a 10-year use cycle, the other two screens are about 6 years old. When the service life is reached, a large area of black screen may appear or the brightness of the projector may be seriously reduced. Generally, a second investment is required to continue the display function. Therefore, based on a 10-year use cycle, the investment cost of a small-pitch LED screen is not higher than that of other types of display screens, and is even in a lower state.
3 Conclusion
Through the understanding of various products of small-pitch LED displays and the research on the look and feel of exhibits and user feedback, it can be judged from the sensory perspective that small-pitch LED displays are fully capable of being applied to large screens in centralized control rooms, and have very outstanding display effects. Especially when the background color of graphics and text is black or dark, the display effect is particularly outstanding, and the power consumption is lower and the lifespan is longer. Measurement test results from the China Institute of Metrology show that small-pitch LED displays are no more harmful to the retina than other types of displays. Long-term viewing of any display screen may cause permanent damage to the human eye. Therefore, no matter what form of display screen is used, operators must pay attention to eye hygiene, develop good eye habits, combine work and rest, and consciously and proactively protect their eyesight.
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